US20180337187A1 - Semiconductor structure for preventing row hammering issue in dram cell and method for manufacturing the same - Google Patents
Semiconductor structure for preventing row hammering issue in dram cell and method for manufacturing the same Download PDFInfo
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B12/00—Dynamic random access memory [DRAM] devices
- H10B12/30—DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B12/00—Dynamic random access memory [DRAM] devices
- H10B12/30—DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells
- H10B12/48—Data lines or contacts therefor
- H10B12/488—Word lines
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- H01L27/10891—
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- H01L27/10814—
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- H01L27/10823—
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B12/00—Dynamic random access memory [DRAM] devices
- H10B12/01—Manufacture or treatment
- H10B12/02—Manufacture or treatment for one transistor one-capacitor [1T-1C] memory cells
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B12/00—Dynamic random access memory [DRAM] devices
- H10B12/01—Manufacture or treatment
- H10B12/02—Manufacture or treatment for one transistor one-capacitor [1T-1C] memory cells
- H10B12/05—Making the transistor
- H10B12/053—Making the transistor the transistor being at least partially in a trench in the substrate
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B12/00—Dynamic random access memory [DRAM] devices
- H10B12/30—DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells
- H10B12/31—DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells having a storage electrode stacked over the transistor
- H10B12/315—DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells having a storage electrode stacked over the transistor with the capacitor higher than a bit line
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B—ELECTRONIC MEMORY DEVICES
- H10B12/00—Dynamic random access memory [DRAM] devices
- H10B12/30—DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells
- H10B12/34—DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells the transistor being at least partially in a trench in the substrate
Definitions
- the present invention relates generally to a semiconductor structure, and more specifically, to a semiconductor structure for preventing a row hammering issue in DRAM cells and methods for manufacturing the same.
- computing devices are smaller and have much more processing power. Additionally, they include more and more storage and memory to meet the needs of the programming and computing performed on the devices.
- the shrinking size of the devices together with the increased storage capacity is achieved by providing higher density devices, where the atomic storage units within a memory device have smaller and smaller geometries.
- the row hammering issue can cause charge migration across the passgate (PG).
- PG passgate
- BLC bit line contact
- the electron may also be easily trapped by electron-hole recombination into a P-well through path 2 . Both conditions would cause data “0” failure.
- DRAM dynamic random access memory
- One objective of the present invention is to provide a semiconductor structure for preventing row hammering issue in DRAM cell.
- the structure is specifically provided an n-type work function metal layer to tune the work function of the buried word line, thereby preventing the row hammering issue resulted from the word line leakage to a non-accessed physically adjacent row.
- the preferred embodiment of the present invention provides a semiconductor structure for preventing row hammering issue in DRAM cell, which include a substrate, a trench, a gate dielectric conformally on the trench, a work function metal layer conformally on the gate dielectric, and a buried word line on the work function metal layer, wherein the work function metal layer includes materials of titanium and titanium nitride, and the ratio of titanium nitride to titanium in the work function metal layer gradually increases from the side of work function metal layer adjacent to the gate dielectric to the other side of work function metal layer adjacent to the buried word line.
- another embodiment of the present invention provides a semiconductor structure for preventing row hammering issue in DRAM cell, which includes a substrate, a trench, a gate dielectric conformally on the trench, an n-type work function metal layer conformally on the gate dielectric, a titanium nitride layer conformally on the n-type work function metal layer, and a buried word line on the titanium nitride layer.
- still another embodiment of the present invention provides a method of manufacturing a semiconductor device for preventing row hammering issue in DRAM cell, which includes the steps of providing a substrate, forming a trench in the substrate, forming a gate dielectric conformally on the trench, forming an n-type work function metal layer conformally on the substrate and the gate dielectric, forming a titanium nitride layer conformally on the n-type work function metal layer, and filling a buried word line in the trench.
- FIG. 1 is a schematic view explaining the row hammering mechanism in a DRAM
- FIG. 2 is a layout of DRAM cells
- FIGS. 3, 5, 6 and 8 are cross-sectional views of the manufacturing processes of a DRAM cell indifferent steps taken along the line A-A′ in FIG. 2 in accordance with one preferred embodiment of the present invention
- FIGS. 4 and 9 are cross-sectional views of the manufacturing processes of a DRAM cell in different steps taken along the line B-B′ in FIG. 2 in accordance with one preferred embodiment of the present invention.
- FIG. 7 is a cross-sectional view of the manufacturing processes of the titanium nitride layer in a DRAM cell taken along the line A-A′ in FIG. 2 in accordance with one preferred embodiment of the present invention.
- FIGS. 2-9 schematically illustrate a method for fabricating a DRAM device according to an preferred embodiment of the present invention, in which FIG. 2 illustrates a top-view diagram, FIG. 3 illustrates a cross-sectional view taken along the sectional line A-A′ in FIG. 2 , FIG. 4 illustrates a cross-sectional view taken along the sectional line B-B′ in FIG. 1 , FIG. 5 illustrates a cross-sectional view following the fabrication of FIG. 3 , and FIG. 8 and FIG. 9 illustrates a cross-sectional view following the fabrication of FIG. 5 and FIG. 6 , respectively.
- the present embodiment pertains to the fabrication of a memory device, and more particularly a dynamic random access memory (DRAM) device 10 with buried gates, in which the DRAM device includes at least one transistor device (not shown) and at least one capacitor structure (not shown) that will be serving as a smallest constituent unit within the DRAM array and also used to receive electrical signals from bit lines 12 and word lines 14 .
- DRAM dynamic random access memory
- the DRAM device 10 includes a substrate 16 such as a semiconductor substrate or wafer made of silicon, at least one shallow trench isolation (STI) 24 formed in the substrate 16 , and a plurality of active areas (AA) 18 defined on the substrate 16 .
- a memory region 20 and a periphery region are also defined on the substrate 16 , in which multiple word lines 14 are preferably formed within the substrate 16 in the memory region 20 and multiple bit lines 12 are preferably formed on the substrate 16 in the memory region 20 , while other active devices (not shown) could be formed on the periphery region.
- STI shallow trench isolation
- AA active areas
- the active regions 18 are disposed, for example, parallel to each other and extending along a first direction, and the word lines 14 or multiple gates (i.e. buried word line) 22 are disposed within the substrate 16 and passing through the active regions 18 and STI 24 .
- the gates 22 are disposed extending along a second direction, such as a y-direction different from the first direction, in which the second direction crosses the first direction at an angle less than 90 degrees.
- bit lines 12 are disposed on the substrate 16 parallel to each other and extending along a third direction, such as a x-direction crossing the active regions 18 and STI 24 , in which the third direction is different from the first direction and preferably orthogonal to the second direction.
- the first direction, second direction, and third direction are all different from each other while the first direction is not orthogonal to both the second direction and the third direction.
- contact plugs including bit line contacts (BLC) (not shown) are formed in the active regions 18 adjacent to two sides of the word lines 14 to electrically connect to source/drain region (not shown) of each transistor element and storage node (SN) contacts (not shown) are formed to electrically connect to a capacitor.
- BLC bit line contacts
- FIGS. 3-4 are cross-sectional views taken along the sectional line A-A′ and the sectional line B-B′ respectively in FIG. 2 .
- a first trench 26 is first formed in the substrate 16 , a shallow trench isolation (STI) 24 is then formed in the first trench 26 , and a second trench 28 is formed adjacent to the first trench 26 , wherein the STI 24 includes a upper portion 30 and a lower portion 32 and the top surface of the upper portion 30 is even with or higher than the bottom surface of the second trench 28 .
- STI shallow trench isolation
- the formation of the STI 24 could be accomplished by first forming a STI (not shown), and then forming a patterned mask (not shown) on the substrate 16 to expose part of the first trench 26 and part of the substrate 16 surrounding the STI.
- An etch process is performed using the patterned mask as a etch mask to form a first trench 26 and a second trench 28 .
- the first trench 26 would be deeper than the second trench 28 since the etch rates for the STI and the substrate 16 in the etch process are different.
- the remaining STI after the etching process now becomes a liner 34 .
- a dielectric layer 36 is filled in the first trench 26 to complete the manufacture of the STI 24 , which include an upper portion 30 made of the dielectric layer 36 and a lower portion 32 made of the liner 34 .
- the liner 34 and the dielectric layer 36 are preferably made of different materials, in which the liner 34 in this embodiment is preferably made of silicon oxide while the dielectric layer 36 is made of silicon nitride.
- an etchant of the aforementioned etching process is selected from the group consisting of CH 3 F and O 2 , and an etching selectivity of silicon oxide to silicon nitride is controlled at 20:1.
- a greater portion of the liner 34 and a smaller or lesser portion of the dielectric layer 36 were removed during the aforementioned etching process so that the top surface of the remaining dielectric layer 36 or top portion 30 of the STI 24 is even with or slightly higher than the bottom surface of the adjacent second trench 28 .
- a gate dielectric 38 is conformally formed on the surface of the first trench 26 and the second trench 28 .
- the gate dielectric 38 preferably includes the silicon oxide formed by an in-situ steam generation (ISSG) process or a high-k dielectric formed by an atomic layer deposition process, in which the high-k dielectric layer is preferably selected from dielectric materials having dielectric constant (k value) larger than 4 .
- the high-k dielectric layer may be selected from hafnium oxide (HfO 2 ), hafnium silicon oxide (HfSiO 4 ), hafnium silicon oxynitride (HfSiON), aluminum oxide (Al 2 O 3 ), lanthanum oxide (La 2 O 3 ), tantalum oxide (Ta 2 O 5 ), yttrium oxide (Y 2 O 3 ), zirconium oxide (ZrO 2 ), strontium titanate oxide (SrTiO 3 ), zirconium silicon oxide (ZrSiO 4 ), hafnium zirconium oxide (HfZrO 4 ), strontium bismuth tantalate (SrBi 2 Ta 2 O 9 , SBT), lead zirconate titanate (PbZr x Ti 1-x O 3 , PZT), barium strontium titanate (BaxSr 1-x TiO 3 , BST) or a combination thereof.
- hafnium oxide HfO 2
- a titanium nitride (TiN) layer would be formed first as a barrier after the gate dielectric is formed to increase the adhesion between the buried word line metal and the gate dielectric and to prevent the volcano effect happening in the tungsten-based word line metal.
- TiN titanium nitride
- an n-type work function metal layer 39 would be first formed on the gate dielectric 38 before the formation of the TiN layer.
- the n-type work function metal layer 39 is formed conformally on the gate dielectric 38 and the substrate 16 , in which the material may be selected from a metal with a work function ranging between 3.9 eV and 4.3 eV, such as but not limited to titanium (Ti), titanium aluminide (TiAl), zirconium aluminide (ZrAl), tungsten aluminide (WAl), tantalum aluminide (TaAl), hafnium aluminide (HfAl), or titanium aluminum carbide (TiAlC).
- the n-type work function layer 39 may adjust the work function of the buried word line formed thereafter, thereby preventing the row hammering issue resulted from the word line leakage to a non-accessed physically adjacent row and relevant data corruption and failure.
- the manufacture of a TiN barrier layer is conducted.
- the TiN layer may be formed by directly transforming the n-type work function layer 39 .
- a nitrogen radical treatment P 1 may be performed to the surface of the n-type work function layer 39 to transform part of the n-type work function metal into TiN.
- the nitrogen radical treatment P 1 may include the steps of introducing nitrogen (N 2 ) and ammonia (NH 3 ) and conducting a high temperature plasma treatment.
- the ratio of TiN to Ti in the processed n-type work function layer 39 a would gradually increase from the side adjacent to the gate dielectric 38 to the surface side.
- the Ti layer with thickness of 50 ⁇ will be partly transformed into an outer TiN portion with thickness of 20 ⁇ after the nitrogen radical treatment.
- the TiN layer 41 may be directly and conformally deposited on the n-type work function layer 39 .
- This approach is suitable to all kinds of n-type work function metal materials rather than just limited to use titanium.
- a conductive layer (not shown) with a thickness about 500 ⁇ is formed on the substrate, in which the material may be selected from low-resistance materials, such as copper (Cu), aluminum (Al), Tungsten (W), titanium-aluminum alloy (TiAl), cobalt tungsten phosphide (CoWP) or any combination thereof.
- low-resistance materials such as copper (Cu), aluminum (Al), Tungsten (W), titanium-aluminum alloy (TiAl), cobalt tungsten phosphide (CoWP) or any combination thereof.
- etching back process is then conducted to remove part of the conductive layer and part of the n-type work function metal layer 39 a outside the trench, so that the conductive layer and the n-type work function metal layer 39 a and the gate dielectric remain only within the trench and have a top surface slightly lower than the surface of the substrate 16 , thereby forming the buried word line 40 .
- a hard mask 42 is formed on the buried word line 40 , in which the top surfaces of the hard mask 42 and the substrate 16 are coplanar.
- the material of the hard mask 42 may be silicon nitride.
- an ion implantation process could be conducted depending on the demand of the process to form doped regions (not shown) such as lightly doped drain or source/drain region in the substrate 16 adjacent to two sides of the buried word line 40 .
- a contact plug process could be conducted to form bit line contacts (BLC) adjacent to two sides of the buried word line 40 electrically connecting the source/drain regions and bit lines formed thereafter and storage node contacts electrically connecting the source/drain region and capacitors fabricated in the later process.
- BLC bit line contacts
Abstract
Description
- This application is a divisional of application Ser. No. 15/627,455, filed on Jun. 20, 2017 and entitled “SEMICONDUCTOR STRUCTURE FOR PREVENTING ROW HAMMERING ISSUE IN DRAM CELL AND METHOD FOR MANUFACTURING THE SAME”, which is incorporated herein by reference.
- The present invention relates generally to a semiconductor structure, and more specifically, to a semiconductor structure for preventing a row hammering issue in DRAM cells and methods for manufacturing the same.
- With advances in computing technology, computing devices are smaller and have much more processing power. Additionally, they include more and more storage and memory to meet the needs of the programming and computing performed on the devices. The shrinking size of the devices together with the increased storage capacity is achieved by providing higher density devices, where the atomic storage units within a memory device have smaller and smaller geometries.
- With the latest generation of increased density, intermittent failure has appeared in some devices. For example, some existing DDR3 based systems experience intermittent failures with heavy workloads. Researchers have traced the failures to repeated access to a single row of memory within the refresh window of the memory cell. For example, for a 32 nm process, the physically adjacent word line (WL) to the accessed row has a very high probability of experiencing data corruption. The failure issue has been labeled as a “row hammer” issue by the DRAM industry where it is frequently seen.
- The row hammering issue can cause charge migration across the passgate (PG). As it is shown in
FIG. 1 , the parasitic electron is easily induced and leaked from passgate (PG) to bit line contact (BLC) throughpath 1 by the repeated access to one row, thereby causing data corruption in a non-accessed physically adjacent row. The electron may also be easily trapped by electron-hole recombination into a P-well throughpath 2. Both conditions would cause data “0” failure. - One approach identified to deal with the failure due to row hammer is to limit the number of accesses allowed per row per refresh cycle, which has performance impacts in the system. Another approach identified to address the row hammer failure includes decreasing the bottom critical dimension (BCD) in the buried channel array transistor (BCAT). However, changing the dimensional sizes of the devices has both physical and practical limitations. To the extent certain dimensions may now be changed, it would still require changes to the manufacturing processes.
- Another approach to dealing with the row hammer issue is to decrease the time between refreshes. However, the refresh time has already been held constant even as the density of the devices has increased. Current devices are required to perform refresh on larger and larger areas in the same period of time. Thus, further decreasing the refresh time would cause a performance impact in the system, such as by requiring additional refresh overhead in the memory devices.
- A need exists for an effective method and mechanism for implementing row hammer avoidance in dynamic random access memory (DRAM). It is desirable to provide such method and mechanism without substantially changing the design of the DRAM or the design of dual inline memory modules (DIMM).
- One objective of the present invention is to provide a semiconductor structure for preventing row hammering issue in DRAM cell. The structure is specifically provided an n-type work function metal layer to tune the work function of the buried word line, thereby preventing the row hammering issue resulted from the word line leakage to a non-accessed physically adjacent row.
- To achieve the objective, the preferred embodiment of the present invention provides a semiconductor structure for preventing row hammering issue in DRAM cell, which include a substrate, a trench, a gate dielectric conformally on the trench, a work function metal layer conformally on the gate dielectric, and a buried word line on the work function metal layer, wherein the work function metal layer includes materials of titanium and titanium nitride, and the ratio of titanium nitride to titanium in the work function metal layer gradually increases from the side of work function metal layer adjacent to the gate dielectric to the other side of work function metal layer adjacent to the buried word line.
- To achieve the objective, another embodiment of the present invention provides a semiconductor structure for preventing row hammering issue in DRAM cell, which includes a substrate, a trench, a gate dielectric conformally on the trench, an n-type work function metal layer conformally on the gate dielectric, a titanium nitride layer conformally on the n-type work function metal layer, and a buried word line on the titanium nitride layer.
- To achieve the objective, still another embodiment of the present invention provides a method of manufacturing a semiconductor device for preventing row hammering issue in DRAM cell, which includes the steps of providing a substrate, forming a trench in the substrate, forming a gate dielectric conformally on the trench, forming an n-type work function metal layer conformally on the substrate and the gate dielectric, forming a titanium nitride layer conformally on the n-type work function metal layer, and filling a buried word line in the trench.
- These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
- The accompanying drawings are included to provide a further understanding of the embodiments, and are incorporated in and constitute apart of this specification. The drawings illustrate some of the embodiments and, together with the description, serve to explain their principles. In the drawings:
-
FIG. 1 is a schematic view explaining the row hammering mechanism in a DRAM; -
FIG. 2 is a layout of DRAM cells; -
FIGS. 3, 5, 6 and 8 are cross-sectional views of the manufacturing processes of a DRAM cell indifferent steps taken along the line A-A′ inFIG. 2 in accordance with one preferred embodiment of the present invention; -
FIGS. 4 and 9 are cross-sectional views of the manufacturing processes of a DRAM cell in different steps taken along the line B-B′ inFIG. 2 in accordance with one preferred embodiment of the present invention; and -
FIG. 7 is a cross-sectional view of the manufacturing processes of the titanium nitride layer in a DRAM cell taken along the line A-A′ inFIG. 2 in accordance with one preferred embodiment of the present invention. - It should be noted that all the figures are diagrammatic. Relative dimensions and proportions of parts of the drawings have been shown exaggerated or reduced in size, for the sake of clarity and convenience in the drawings. The same reference signs are generally used to refer to corresponding or similar features in modified and different embodiments.
- Referring to
FIGS. 2-9 ,FIGS. 2-9 schematically illustrate a method for fabricating a DRAM device according to an preferred embodiment of the present invention, in whichFIG. 2 illustrates a top-view diagram,FIG. 3 illustrates a cross-sectional view taken along the sectional line A-A′ inFIG. 2 ,FIG. 4 illustrates a cross-sectional view taken along the sectional line B-B′ inFIG. 1 ,FIG. 5 illustrates a cross-sectional view following the fabrication ofFIG. 3 , andFIG. 8 andFIG. 9 illustrates a cross-sectional view following the fabrication ofFIG. 5 andFIG. 6 , respectively. Preferably, the present embodiment pertains to the fabrication of a memory device, and more particularly a dynamic random access memory (DRAM)device 10 with buried gates, in which the DRAM device includes at least one transistor device (not shown) and at least one capacitor structure (not shown) that will be serving as a smallest constituent unit within the DRAM array and also used to receive electrical signals frombit lines 12 andword lines 14. - As shown in
FIG. 2 , which is a top view of the DRAM device in the present invention, theDRAM device 10 includes asubstrate 16 such as a semiconductor substrate or wafer made of silicon, at least one shallow trench isolation (STI) 24 formed in thesubstrate 16, and a plurality of active areas (AA) 18 defined on thesubstrate 16. In addition, amemory region 20 and a periphery region (not shown) are also defined on thesubstrate 16, in whichmultiple word lines 14 are preferably formed within thesubstrate 16 in thememory region 20 andmultiple bit lines 12 are preferably formed on thesubstrate 16 in thememory region 20, while other active devices (not shown) could be formed on the periphery region. For simplicity purposes, it should be noted that only devices or elements on thememory region 20 are shown inFIG. 1 while elements on the periphery region are omitted. - In this embodiment, the
active regions 18 are disposed, for example, parallel to each other and extending along a first direction, and theword lines 14 or multiple gates (i.e. buried word line) 22 are disposed within thesubstrate 16 and passing through theactive regions 18 andSTI 24. Preferably, thegates 22 are disposed extending along a second direction, such as a y-direction different from the first direction, in which the second direction crosses the first direction at an angle less than 90 degrees. - On the other hand, the
bit lines 12 are disposed on thesubstrate 16 parallel to each other and extending along a third direction, such as a x-direction crossing theactive regions 18 andSTI 24, in which the third direction is different from the first direction and preferably orthogonal to the second direction. In other words, the first direction, second direction, and third direction are all different from each other while the first direction is not orthogonal to both the second direction and the third direction. Preferably, contact plugs including bit line contacts (BLC) (not shown) are formed in theactive regions 18 adjacent to two sides of theword lines 14 to electrically connect to source/drain region (not shown) of each transistor element and storage node (SN) contacts (not shown) are formed to electrically connect to a capacitor. - The fabrication of buried
word lines 14 is explained below. As shown inFIGS. 3-4 , which are cross-sectional views taken along the sectional line A-A′ and the sectional line B-B′ respectively inFIG. 2 , afirst trench 26 is first formed in thesubstrate 16, a shallow trench isolation (STI) 24 is then formed in thefirst trench 26, and asecond trench 28 is formed adjacent to thefirst trench 26, wherein the STI 24 includes aupper portion 30 and alower portion 32 and the top surface of theupper portion 30 is even with or higher than the bottom surface of thesecond trench 28. - Specifically, the formation of the
STI 24 could be accomplished by first forming a STI (not shown), and then forming a patterned mask (not shown) on thesubstrate 16 to expose part of thefirst trench 26 and part of thesubstrate 16 surrounding the STI. An etch process is performed using the patterned mask as a etch mask to form afirst trench 26 and asecond trench 28. Thefirst trench 26 would be deeper than thesecond trench 28 since the etch rates for the STI and thesubstrate 16 in the etch process are different. The remaining STI after the etching process now becomes aliner 34. In order to have thefirst trench 26 and thesecond trench 28 with same depth, adielectric layer 36 is filled in thefirst trench 26 to complete the manufacture of theSTI 24, which include anupper portion 30 made of thedielectric layer 36 and alower portion 32 made of theliner 34. - In this embodiment, the
liner 34 and thedielectric layer 36 are preferably made of different materials, in which theliner 34 in this embodiment is preferably made of silicon oxide while thedielectric layer 36 is made of silicon nitride. Preferably, an etchant of the aforementioned etching process is selected from the group consisting of CH3F and O2, and an etching selectivity of silicon oxide to silicon nitride is controlled at 20:1. In other words, a greater portion of theliner 34 and a smaller or lesser portion of thedielectric layer 36 were removed during the aforementioned etching process so that the top surface of the remainingdielectric layer 36 ortop portion 30 of theSTI 24 is even with or slightly higher than the bottom surface of the adjacentsecond trench 28. - Next, as shown in
FIG. 5 , which is a schematic cross-sectional view following the process inFIG. 3 , agate dielectric 38 is conformally formed on the surface of thefirst trench 26 and thesecond trench 28. Thegate dielectric 38 preferably includes the silicon oxide formed by an in-situ steam generation (ISSG) process or a high-k dielectric formed by an atomic layer deposition process, in which the high-k dielectric layer is preferably selected from dielectric materials having dielectric constant (k value) larger than 4. For instance, the high-k dielectric layer may be selected from hafnium oxide (HfO2), hafnium silicon oxide (HfSiO4), hafnium silicon oxynitride (HfSiON), aluminum oxide (Al2O3), lanthanum oxide (La2O3), tantalum oxide (Ta2O5), yttrium oxide (Y2O3), zirconium oxide (ZrO2), strontium titanate oxide (SrTiO3), zirconium silicon oxide (ZrSiO4), hafnium zirconium oxide (HfZrO4), strontium bismuth tantalate (SrBi2Ta2O9, SBT), lead zirconate titanate (PbZrxTi1-xO3, PZT), barium strontium titanate (BaxSr1-xTiO3, BST) or a combination thereof. - For the conventional process in prior art, a titanium nitride (TiN) layer would be formed first as a barrier after the gate dielectric is formed to increase the adhesion between the buried word line metal and the gate dielectric and to prevent the volcano effect happening in the tungsten-based word line metal. However, in order to solve the aforementioned row hammering issue frequently happening in the word line, as shown in
FIG. 5 in the embodiment of the present invention, an n-type workfunction metal layer 39 would be first formed on thegate dielectric 38 before the formation of the TiN layer. The n-type workfunction metal layer 39 is formed conformally on thegate dielectric 38 and thesubstrate 16, in which the material may be selected from a metal with a work function ranging between 3.9 eV and 4.3 eV, such as but not limited to titanium (Ti), titanium aluminide (TiAl), zirconium aluminide (ZrAl), tungsten aluminide (WAl), tantalum aluminide (TaAl), hafnium aluminide (HfAl), or titanium aluminum carbide (TiAlC). The n-typework function layer 39 may adjust the work function of the buried word line formed thereafter, thereby preventing the row hammering issue resulted from the word line leakage to a non-accessed physically adjacent row and relevant data corruption and failure. - After the n-type work
function metal layer 39 is formed, the manufacture of a TiN barrier layer is conducted. In one embodiment of the present invention, the TiN layer may be formed by directly transforming the n-typework function layer 39. As shown inFIG. 6 , in the condition that titanium is used as the material of the n-typework function layer 39, a nitrogen radical treatment P1 may be performed to the surface of the n-typework function layer 39 to transform part of the n-type work function metal into TiN. The nitrogen radical treatment P1 may include the steps of introducing nitrogen (N2) and ammonia (NH3) and conducting a high temperature plasma treatment. Through this treatment, the ratio of TiN to Ti in the processed n-typework function layer 39 a would gradually increase from the side adjacent to thegate dielectric 38 to the surface side. For example, the Ti layer with thickness of 50 Å will be partly transformed into an outer TiN portion with thickness of 20 Å after the nitrogen radical treatment. - In another embodiment of the present invention, as shown in
FIG. 7 , theTiN layer 41 may be directly and conformally deposited on the n-typework function layer 39. This approach is suitable to all kinds of n-type work function metal materials rather than just limited to use titanium. - After the TiN layer or portion is formed, as shown in
FIG. 8 , a conductive layer (not shown) with a thickness about 500 Å is formed on the substrate, in which the material may be selected from low-resistance materials, such as copper (Cu), aluminum (Al), Tungsten (W), titanium-aluminum alloy (TiAl), cobalt tungsten phosphide (CoWP) or any combination thereof. An etching back process is then conducted to remove part of the conductive layer and part of the n-type workfunction metal layer 39 a outside the trench, so that the conductive layer and the n-type workfunction metal layer 39 a and the gate dielectric remain only within the trench and have a top surface slightly lower than the surface of thesubstrate 16, thereby forming the buriedword line 40. Next, ahard mask 42 is formed on the buriedword line 40, in which the top surfaces of thehard mask 42 and thesubstrate 16 are coplanar. The material of thehard mask 42 may be silicon nitride. - Afterward, an ion implantation process could be conducted depending on the demand of the process to form doped regions (not shown) such as lightly doped drain or source/drain region in the
substrate 16 adjacent to two sides of the buriedword line 40. Finally, a contact plug process could be conducted to form bit line contacts (BLC) adjacent to two sides of the buriedword line 40 electrically connecting the source/drain regions and bit lines formed thereafter and storage node contacts electrically connecting the source/drain region and capacitors fabricated in the later process. - Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.
Claims (11)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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US16/028,364 US10685964B2 (en) | 2017-05-18 | 2018-07-05 | Semiconductor structure for preventing row hammering issue in DRAM cell and method for manufacturing the same |
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CN108962892B (en) * | 2017-05-26 | 2021-02-26 | 联华电子股份有限公司 | Semiconductor element and manufacturing method thereof |
US11282933B2 (en) * | 2017-11-30 | 2022-03-22 | Taiwan Semiconductor Manufacturing Co., Ltd. | FinFET having a work function material gradient |
KR102540965B1 (en) * | 2018-10-17 | 2023-06-07 | 삼성전자주식회사 | Semiconductor device |
US10727232B2 (en) | 2018-11-07 | 2020-07-28 | Applied Materials, Inc. | Dram and method of making |
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US11227926B2 (en) * | 2020-06-01 | 2022-01-18 | Nanya Technology Corporation | Semiconductor device and method for fabricating the same |
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Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130140682A1 (en) * | 2011-12-01 | 2013-06-06 | Chi-Wen Huang | Buried word line and method for forming buried word line in semiconductor device |
US20140004693A1 (en) * | 2012-07-02 | 2014-01-02 | Globalfoundries Inc. | Methods for fabricating integrated circuits having improved metal gate structures |
US20150214314A1 (en) * | 2014-01-29 | 2015-07-30 | SK Hynix Inc. | Dual work function buried gate type transistor and method for fabricating the same |
US20160204201A1 (en) * | 2015-01-09 | 2016-07-14 | Jeonghoon Oh | Semiconductor devices having channels with retrograde doping profile |
US20160276273A1 (en) * | 2014-12-18 | 2016-09-22 | SK Hynix Inc. | Semiconductor device with air gap and method for fabricating the same |
US20160315088A1 (en) * | 2015-04-22 | 2016-10-27 | SK Hynix Inc. | Semiconductor device having buried gate structure and method for manufacturing the same, memory cell having the same and electronic device having the same |
US20170125422A1 (en) * | 2015-10-28 | 2017-05-04 | SK Hynix Inc. | Semiconductor device having buried gate structure, method for manufacturing the same, memory cell having the same, and electronic device having the same |
US20170125532A1 (en) * | 2015-10-29 | 2017-05-04 | SK Hynix Inc. | Semiconductor structure having buried gate structure, method for manufacturing the same, and memory cell having the same |
US20170186844A1 (en) * | 2015-12-23 | 2017-06-29 | SK Hynix Inc. | Semiconductor device having buried gate structure, method for manufacturing the same, and memory cell having the same |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100855967B1 (en) * | 2007-01-04 | 2008-09-02 | 삼성전자주식회사 | Semiconductor having buried word line cell structure and a method of fabricating the same |
US9099526B2 (en) * | 2010-02-16 | 2015-08-04 | Monolithic 3D Inc. | Integrated circuit device and structure |
KR101749055B1 (en) * | 2010-10-06 | 2017-06-20 | 삼성전자주식회사 | A semiconductor device and a method of forming the same |
US9384962B2 (en) * | 2011-04-07 | 2016-07-05 | United Microelectronics Corp. | Oxygen treatment of replacement work-function metals in CMOS transistor gates |
US8507338B2 (en) * | 2011-08-08 | 2013-08-13 | United Microelectronics Corp. | Semiconductor structure and fabricating method thereof |
US8872286B2 (en) * | 2011-08-22 | 2014-10-28 | United Microelectronics Corp. | Metal gate structure and fabrication method thereof |
US8691681B2 (en) * | 2012-01-04 | 2014-04-08 | United Microelectronics Corp. | Semiconductor device having a metal gate and fabricating method thereof |
KR102029923B1 (en) * | 2013-05-31 | 2019-11-29 | 에스케이하이닉스 주식회사 | Method for manufacturing semiconductor device with side contact |
US9105720B2 (en) * | 2013-09-11 | 2015-08-11 | United Microelectronics Corp. | Semiconductor device having metal gate and manufacturing method thereof |
KR102162733B1 (en) * | 2014-05-29 | 2020-10-07 | 에스케이하이닉스 주식회사 | Dual work function bruied gate type transistor, method for manufacturing the same and electronic device having the same |
US9953984B2 (en) * | 2015-02-11 | 2018-04-24 | Lam Research Corporation | Tungsten for wordline applications |
CN106531618B (en) * | 2015-09-15 | 2021-05-18 | 联华电子股份有限公司 | Work function adjusting method for semiconductor element with metal gate structure |
CN106558482B (en) * | 2015-09-25 | 2019-12-24 | 中芯国际集成电路制造(上海)有限公司 | Semiconductor device and manufacturing method thereof |
-
2017
- 2017-05-18 CN CN201710351696.6A patent/CN108962891B/en active Active
- 2017-06-20 US US15/627,455 patent/US10043811B1/en active Active
-
2018
- 2018-07-05 US US16/028,364 patent/US10685964B2/en active Active
-
2020
- 2020-05-05 US US16/866,573 patent/US11239243B2/en active Active
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130140682A1 (en) * | 2011-12-01 | 2013-06-06 | Chi-Wen Huang | Buried word line and method for forming buried word line in semiconductor device |
US20140004693A1 (en) * | 2012-07-02 | 2014-01-02 | Globalfoundries Inc. | Methods for fabricating integrated circuits having improved metal gate structures |
US20150214314A1 (en) * | 2014-01-29 | 2015-07-30 | SK Hynix Inc. | Dual work function buried gate type transistor and method for fabricating the same |
US20160276273A1 (en) * | 2014-12-18 | 2016-09-22 | SK Hynix Inc. | Semiconductor device with air gap and method for fabricating the same |
US20160204201A1 (en) * | 2015-01-09 | 2016-07-14 | Jeonghoon Oh | Semiconductor devices having channels with retrograde doping profile |
US20160315088A1 (en) * | 2015-04-22 | 2016-10-27 | SK Hynix Inc. | Semiconductor device having buried gate structure and method for manufacturing the same, memory cell having the same and electronic device having the same |
US20170125422A1 (en) * | 2015-10-28 | 2017-05-04 | SK Hynix Inc. | Semiconductor device having buried gate structure, method for manufacturing the same, memory cell having the same, and electronic device having the same |
US20170125532A1 (en) * | 2015-10-29 | 2017-05-04 | SK Hynix Inc. | Semiconductor structure having buried gate structure, method for manufacturing the same, and memory cell having the same |
US20170186844A1 (en) * | 2015-12-23 | 2017-06-29 | SK Hynix Inc. | Semiconductor device having buried gate structure, method for manufacturing the same, and memory cell having the same |
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US11239243B2 (en) | 2022-02-01 |
US10685964B2 (en) | 2020-06-16 |
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US10043811B1 (en) | 2018-08-07 |
US20200266199A1 (en) | 2020-08-20 |
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